Determination of Variety Effect of a Simple Cotton Picking Machine on Design Parameters

This study was made in order to determine how much the type of cotton affects the design parameters such as vacuum pressure, suction speed and break-off force in a simple cotton picking machinery. The vacuum pressure, suction speed and curl break-off forces belonging to the cotton types of DPXxC//BixLa hybrid and Nazilli 84 which is stili being developed in accordance with the mechanical harvesting were measured. The statistical relationships between measured design parameters and cotton variety were searched. It was observed that there is no statistical difference between types in aspect of suction speed and values of vacuum pressure where as the types differ in aspect of lock break-off force. The lock break-off force of the type of Nazilli 84 was been found lower than the kind which is stili being developed. Although the break-off forces of cotton variety are different it is observed that suction speed of 2 m in average and a vacuum pressure of —5 kPa is sufficient for the locks to be broken off from the bolls.


Introduction
Cotton is an important and strategical agricultural product.One of the major problems faced with in cotton which is grown in different sizes of areas is harvest (Tunçer and I şı k 1999).In Turkey a great portion of cotton harvest is realised by human labor force.However the tendency of increase in labor costs leads the producers towards harvest with machinery (Sabanc ı and I şı k 1989, Evcim and Öz 1997).The harvesting machinery used in Turkey are the big capacity ones running with generally mechanical principle.The cotton harvesting with big capacity machinery can be economical only in establishments with big production sites or estabilishments which has long duration for usage within the year (Evcim 1996 ).It seems that this machinery can not be used in small areas because of their physical properties.Considering the current cotton facilities in Turkey it would be beneficial to develope a simple machinery decreasing the requirement for labor force.Whether the design parameters to be used in the development of machinery will vary in accordance with the types or not is an important knowledge which shall make design much easier.

Materials and Methods
The schematical appearance of cotton picking machinery designed has been illustrated in Figure 1.The machinery consists of a picking edge of the brim diameter of which can be adjusted, a vacuum storage the below lid of which can be opened, a depot where the cotton harvested is collected and a vacuum unit imposed from a movable power source.
A simulation mechanism in Figure 2 has been formed to determine the design parameters related with the machinery.In this mechanism is an electricity engine of 1 kW, a vacuum unit providing vacuum up to 0.025 m 3 s a n d -7 0 k P a ' s , t w o v a c u u m m e t e r s , t w o c i r c u l a r v a l v e s , a square wire strainer with the dimension of 1x1, an air channel consisted of PVC pipe and a material connecting apparatus.In the measurements a flow measure with telescoic probe with the measurement interval of 0,0001-195 m s -1 , a dynamometer with the sensitivity of 0,001 and measurement interval of 0-2 kg, a vacuum meter with the sensitivity of -1 kPa and measurement intervai of 0 and -100 kPa were used.The cottons used in the trials DPXxC//BixLa hybrid representing 5 lines formed by the combinat ı on hybrids of Deltapine DPX, Cocker 4104, Beliizvor and La 566 FN developed in accordance with the mechanical harvesting and the type of Nazilli 84.The averages of the values belonging to the physio-mechanical and fiber properties belonging to the varieties of cotton were presented in Table 1.
The properties of kinds have been giyen in literature (Kaynak et all. 2001).
The varieties of cotton used in trials were picked from the parcels grown as 3 repetitions in accordance with randomized bock desing trials.450 cotton bollscons ı sting of 25 each repetition were picked in the harvesting period (.15th -30`h October) The bolls were tied to the dynamometer on the simulation mechanism as a rigid in a way resembling the method indicated in the literature (Dilbeck and Quisenberry 1979).The locks in four carpel inside of bolls were broken off with the effect of vacuum by opening circular valve in air the channel.The break-off force, vacuum pressure and air flow values were measured at the moment the locks were broken off from the carpel.The locks were prevented from going through the channel with a strainer inserted in air channel.Totally 1800 trials have been made.The adjusted picking edge in the designed cotton picking machine must be used by the worker.As this moving unit was pulled closer or pushed further towards locks under the control of the worker this case was reflected to simulation mechanism.As the breaking off of the locks were taken as the base, the distance between the edge of picking and locks was not taken into consideration.In the trials the diameter of the smallest hole of the picking edge through which the locks pass was taken as fıxed.The breaking off value measured in terms of mass with the calculations made after measurements was converted into the force by using the equation of the flow value measured in air channel was converted into the value of suction speed in air channel by using the equation of This value was converted into value of suction speed at the edge point of the channel by using the equation of V. D2 Vs = ( 3 ) D2 e

Results and Discussion
The averages of the measured design parameters were giyen in Table 2 in accordance with the variety of cotton.The values of vacuum pressure, suction speed (Vs ) and break-off force are respectively -4,132 kPa, 1.676 m s -1 , 0.393 N in the hybrid of DPXxC//BixLa and 3.528 kPa, 1.620 m s -1 , 0.284 N in the type of Nazilli 84.The values of break off force match with the literature data (Yelin 1985).
The variance analysis was made to determine whether there is difference between the varieties in aspect of design parameters.The results obtained were presented in Table 3.
When we observe Table 3, we see that there is difference in aspect of lock break off force statistically between DPXxC//BixLa hybrid and the variety of Nazilli 84.There is no difference between repetitions.

Table 2. The repetition averages belonging to design parameters
The force of lock break off of the type Nazilli 84 ;s much lower than the hybrid type of DPXxC//BiLa.This case is a positive indicator for the appropriateness of the hybrid type of DPXxC//BiLa which is being developed for the mechanical harvesting.As the lock break off force is not the direct running value of the machinery designed the difference likely to occur between types will not affect the design of machinery directly.The fact that there is no statistical difference between vacuum pressure and suction speed (Vs ) forming the running values of designed machinery shows that the machinery can be used in different ways.
Although the break off forces of varieties of cotton which used in research are different from each other we can say that the lock in the cotton bolls can be broken off with the suction speed of average 2 m s -1 and a vacuum pressure of -5 kPa.
The values of suction speed and vacuum pressure found at the end of trials are below the values of suction speed and vacuum pressure to be obtained from a pneumatic planting machine (Önal 1995).That's why some revisions can be made during the development of cotton picking machine and the vacuum units of pneumatic planting machines can be used.
The farm trials should be made to show the effect of designed picking machines on human labor force and efficiency as well as their analysis in the aspect of economics in accordance with the harvest made with human labor force and big harvest machinery.

Symbols
Figure 1.Designed cotton picking machinery

:
Diameter of air channel (m) : Diameter of edge point of air channel (m) : Force off lock break-off (N) : Acceleration of gravity (m s -2 ) Break off value measured in terms of mass (kg) : Air flow measured in air channel (m 3 s-1 ) : Suction speed at the air channel (m s -1 ) : Suction speed at the edge point of air channel (m s )